Explorer I was the first American satellite. It was launched four months after the first artificial satellite, Sputnik I, was put into orbit by the Soviet Union, beginning the so-called space race. Although it carried a number of instruments, Explorer I was relatively small, weighing just 30 lbs (13 kg). It stopped transmission of data later in 1958, when its batteries died, but remained in orbit for more than 12 years. Where did it make its fiery reentry? Discuss
Source: The Free Dictionary
An aerogel is a highly porous solid formed from a gel, such as silica gel, in which the liquid is replaced with a gas. The lightest is less than four times as dense as dry air. Silica-based aerogels are among the lightest, and some, nicknamed “solid smoke” or “frozen smoke,” are nearly transparent. Heavier aerogels were first developed in 1931 and have been used to detect high-energy particles emitted by particle accelerators. What are some other applications of aerogels in everyday products? Discuss
Source: The Free Dictionary
Definition: (adjective) In a straight unbroken line of descent from parent to child.
Synonyms: direct.
Usage: Du Bois, the present librarian of Ardis, is a lineal descendant of this revolutionary pair.
Discuss
Source: The Free Dictionary
Clothing in the ancient world served more than just a protective function; it reflected climatic necessity, class distinctions, and religious beliefs. Ornamentation was an important part of ancient clothing, and charms, trophies, and other valuables were worn to enhance attractiveness and signify one’s social position. In ancient Egypt, for example, jewelry was used to symbolize power and religious standing. What was the purpose of wearing a cone of ox tallow and myrrh on top of the head? Discuss
Source: The Free Dictionary
Definition: (noun) A soft moist mass of bread, meal, clay, or other adhesive substance, usually heated, spread on cloth, and applied to warm, moisten, or stimulate an aching or inflamed part of the body.
Synonyms: cataplasm, plaster.
Usage: I heard from the ship’s doctor that he had been obliged to put a large mustard poultice on this very gentleman’s stomach.
Discuss
Source: The Free Dictionary
In Christianity, a sanctuary lamp is a flame or lamp, usually red, placed in a prominent position in the sanctuary of a church. When lit, it indicates the presence of the Blessed Sacrament—the consecrated elements of the Eucharist. In Judaism, the sanctuary lamp is known by its Hebrew name, ner tamid, which means “eternal light” or “eternal flame.” In a synagogue or temple, the ner tamid hangs above the ark containing the Torah scrolls and is never allowed to go out. How is this achieved? Discuss
Source: The Free Dictionary
Definition: (adjective) Lacking adult maturity or experience; immature.
Synonyms: unfledged.
Usage: Although he is 25, he still behaves like a callow youth in some ways.
Discuss
Source: The Free Dictionary
One of the world’s most heavily used shipping lanes, the Suez Canal extends 101 mi (163 km) from Port Said to the Gulf of Suez and connects the Red Sea with the Mediterranean Sea, allowing ships to sail directly between the Mediterranean and the Indian Ocean. After its completion in 1869, its ownership remained in French and British hands until Egypt nationalized it in 1956, sparking an international crisis, during which it was closed for one of the two times in its history. When was the second? Discuss
Source: The Free Dictionary
Definition: (adjective) Bulky of body; portly.
Synonyms: rotund.
Usage: In his later years, the once-svelte cat took on a more corpulent frame as his mobility decreased.
Discuss
Source: The Free Dictionary
In folklore, an ondine is a female water nymph who can acquire a soul by marrying a human man and bearing a child. The legend is the subject of many works of fiction, including German novelist Baron de La Motte-Fouqué’s fairy tale Undine and French dramatist Jean Giraudoux’s play Ondine. In some versions of the myth, Ondine curses an unfaithful partner to stop breathing if he ever falls asleep. This tale gives its name to Ondine’s curse, a real medical condition involving what? Discuss
Source: The Free Dictionary